Novotechnik Messwertaufnehmer OHG, based in Germany, is a leading manufacturer of qualitatively high-grade potentiometric position transducers and rotary sensors. These sensors are predominantly used in automotive and mechanical engineering processes. Since the end of 2000 Novotechnik has employed Openair® plasma under cleanroom conditions in their production line for activating printed circuit boards before coating. Since the introduction of the Plasmatreat technology, this sensor manufacturer has produced and supplied a total of activated individual components in excess of 50 million and, according to the company, not a single problem has occurred with the adhesion of the coating.
The circuit boards are printed with electrically conductive ink in a screen printing process. Activation with plasma is a prerequisite to ensure safe wetting of the substrate with the conductive ink as well as to achieve good adhesion of the ink to the substrate.For a long time, Novotechnik had executed their pretreatments using low pressure plasma in a vacuum chamber. This method was effective but not suited for the pretreatment of large quantities. The process times used to be too long, and integration into the existing screen printing production lines was not possible. Adding to this was the labor-intensive operation for equipping the vacuum chamber. The Openair®-process put an end to all these limitations.
The rotary nozzle used in this application takes at most one second for the activation of one circuit board panel. At Novotechnik, the installation is adequately sized to handle several screen printing lines simultaneously. Another positive and important effect aside from the activation: The Openair® plasma flowing onto the surface at almost ultrasonic speed also removes particles adhering to the surface and neutralizes the electrostatic charge of the circuit board after unpacking.
Novotechnik Messwertaufnehmer OHG